A. Paper Checks—Functions Served by Paper Checks and How Paper Checks Were Physically Processed Historically
Conceptually, a paper check is a vehicle for two things: 1) the data pertinent to the financial transaction; and 2) evidence of the authorization given by the check writer (the “payer”) to transfer funds from the payer's account to the designated payee and evidence that the financial information was accurately extracted and recorded from the check.
Historically, the processing of paper check transactions was slow and labor-intensive. When one entity (“payer”) paid another entity (“payee”) with a paper check, the payee would physically transport the paper check to its own bank, i.e. a bank with which the payee had an account. The payee's bank would process the check, by reading and recording pertinent information about the transaction represented by the check. The payee's bank would sort by payers' bank all of the checks it received within a given period and physically transport those checks to the payers' banks. The payer bank would then read and record the pertinent information about the transaction contained on the check and make the appropriate debit entry to the payer's account. The payer bank would then transfer funds to the payee's bank. Finally, the payee's bank would make the appropriate credit entry to the payee's account.
The physical transport and handling of the paper checks was highly inefficient. Further, both the payer and payee banks had to process the check to collect and record pertinent information, with such double processing is time-consuming and prone to error.
B. Electronic Processing of Check Transaction
The digital age has ushered in a new approach to processing checks. Over the past decade, there has been an industry transition to the electronic processing of checks. Electronic processing involves the recordation of the data (hereafter “transaction information”) presented by the check into a digital format which can then be transferred electronically, via the internet or other connection between computer networks, between and amongst independent entities (such as banks and third party processors) without the need to physically transfer the paper check. Transaction information includes:                the amount of the check;        the routing number of the bank holding the account on which the check is written;        the account number of the payer;        the check number; and        the date of the check.        
By converting the transaction information described by the check into digital form that can be electronically transmitted, it is not always necessary to physically move the paper check from one entity to another to accomplish the proper debiting and crediting of the financial transaction. Electronic transfers of funds from a payer to a payee (or, more precisely, from the account of the payer to the account of the payee) are facilitated by the Automated Clearing House Network (ACH).
There remain, however, a number of functions served by the paper check that are not served by the digital file of the transaction data. For example, the paper check can be used as evidence that the transaction was authorized by the check writer, or conversely that the check was forged. The paper check can be used as proof that there was an error in the capture of transaction information. An endorsement and appropriate stamp(s) on the paper check provides proof that the transaction was paid, thereby acting as a receipt. Further, when a check bounces due to insufficient funds, the paper check can be returned and is proof that the payer owes the payee the designated amount and that the amount has not been paid.
D. Check 21—Image Exchange and Substitute Checks
To accommodate the two competing ideals of getting rid of the burdens of handling paper checks and maintaining a paper document that can be used as proof when necessary, the U.S. federal government recently has passed legislation (“Check Clearing for the 21st Century Act”; hereafter “Check 21”) that creates a negotiable instrument called a “substitute check”. The substitute check is a paper reproduction that is generated from a stored digital image of the original check. The original check can be scanned and its digital image stored for later use in generating the substitute check. The original check can then be safely destroyed or disposed of.
If a substitute check meets the requirement of the Act, then it is the equivalent of an original paper check. A substitute check has the following physical characteristics:                contains an image of the front and back of the original check;        bears a MICR (Magnetic Ink Character Recognition) line containing all the information appearing on the MICR line of the original check;        conforms, in paper stock, dimension, and otherwise, with generally applicable industry standards; and        is suitable for automated processing in the same manner as the original check.E. Point of Purchase (POP) Conversion        
The National Automated Clearing House Association (NACHA) develops operating rules and business practices for the Automated Clearing House (ACH) Network and for electronic payments in the areas of Internet commerce, electronic bill and invoice presentment and payment (EBPP, EIPP), e-checks, financial electronic data interchange (EDI), international payments, and electronic benefits transfer (EBT). NACHA's rules have, since 2000, provided for merchants to convert checks to an ACH debit at the point of purchase (“POP conversion”). NACHA's POP conversion rules required merchants to obtain the explicit authorization (i.e. signature) of the consumer to debit their account. The merchant then returns the check to the consumer along with a receipt as required by the NACHA POP rules and regulations. At their option, merchants may keep an image of the check, though POP conversion rules do not require that the merchant keep an image of the check.
F. Back Office Conversion and New NACHA Rules
An alternative method of handling checks has been proposed by NACHA for “back office conversion” (BOC), by which merchants scan their checks in a back office, typically at the end of a day. The scanners capture an image of the check and store the image with the MICR data from the check. A file containing this information is then transferred to a bank or third party payment processor.
NACHA has passed this rule, to accommodate back office conversion, which goes into effect on Mar. 16, 2007. These rules require that a digital image of the front of the check be retained for two years, a notice provided to the consumer at point-of-sale prior to the acceptance of the check of payment, and a receipt provided to the consumer with language as depicted by NACHA and the Federal Reserve under Regulation E.